The economic conversion of solar energy into electrical or thermal energy requires a relatively high solar flux impinging on the conversion device. Consequently, there have been numerous attempts to collect the generally diffused sunlight falling on relatively large areas, concentrating it into a small area for more efficient conversion of the radiant energy to a more useful form of energy.
One type of solar concentrating device receiving increasing attention consists of a large area of fluorescent material on which solar radiation impinges, and as a consequence thereof, the fluorescent material emits radiation which is internally reflected within the collector and directed toward a smaller area where it is optically coupled, for example, to an energy conversion device, such as a photovoltaic cell. Examples of such devices are given in U.S. Pat. No. 4,149,902 and U.S. Pat. No. 4,188,238. Indeed, in U.S. Pat. No. 4,149,902, the photovoltaic device is contiguous with the fluorescent collector. In one embodiment of U.S. Pat. No. 4,175,980, however, the photo-voltaic device is not contiguous with the fluorescent collector, but is separated from the concentrator by means of a fiber optic mechanism.
Whatever advantages there may be in devices of the type disclosed in the above-mentioned patents, there still remains a need for efficiently joining a large surface area planar concentrator to a fiber optic bundle or light pipe for transmission of the electromagnetic radiation concentrated in the planar concentrator to a point of use.